The invention relates to a single-phase or multi-phase reaction device capable of effectively improving the mixing intensity and the mass transfer rate and belongs to the technical field of chemical equipment. A shell of the single-phase or multi-phase reaction device consists of a feed end cover, a discharge end cover and a barrel and is fixed on a base; a transmission shaft penetrates through the barrel and is fixed by two bearing pedestals; an isolation ring disc divides the shell into two intervals, namely a mixing chamber and a separation chamber; the mixing chamber consists of the feed end cover, a mass transfer disc and the isolation ring disc; a feed through hole is formed in the feed end cover and is connected with the mixing chamber; the separation chamber consists of the isolation ring disc, an impeller and the discharge end cover; the mass transfer disc and the impeller are fixed on the transmission shaft and rotate along with the transmission shaft; reaction fluid enters the separation chamber and is centrifugally separated by the impeller fixed on the transmission shaft, a heavy phase is thrown to the outer ring of the shell, and a light phase is extruded to the periphery of the transmission shaft by the heavy phase; a light-phase discharge through hole is formed in a position, close to the transmission shaft, on the surface of the discharge end cover; a heavy-phase discharge through hole is formed outside the surface of the discharge end cover. The device can effectively improve the mixing intensity and the mass transfer efficiency.